New concerns have surfaced over the delivery of Scotland's ferries after the Scottish Government's ferry owners and procurers indicated they will not accept delivery if not fully dual fuel.

It comes as it emerged there have been questions from within nationalised Ferguson Marine about whether issues regarding the use of liquefied natural gas (LNG) could be a risk to the project.

The two lifeline ferries, Glen Sannox and Glen Rosa were to be able to operate on LNG which the Scottish Government ferry owners and procurers Caledonian Maritime Assets Ltd (CMAL) said was "significantly cleaner and will help to reduce emissions to meet ambitious Scottish Government targets".

Both ships were lauded by then First Minister Nicola Sturgeon as the 'sustainable' ferries that would "contribute to Scotland's world-leading climate change goals".

CMAL has previously said that the two vessels would reduce the carbon footprint of the ferry fleet by 25 %.

READ MORE: Taxpayer millions 'lost' in new ferry fiasco 'farce'

After a series of issues with the 'green' fuel, Ferguson Marine's chief executive David Tydeman said in his latest update that while steady progress was being made with the LNG system "we still have some risks associated with the final installation of the special, low temperature pipework by the contractor".

It has emerged that CMAL has said that it won't take delivery unless the LNG system is working.

In a record of a CMAL June board meeting CMAL's chief executive Kevin Hobbs said "we have made it clear that the MVGS (Glen Sannox) should only be handed over with all systems fully commissioned (so fully dual fuel).

The Herald:

He also raised concerns about "the lack of engagement and understanding regarding sea trials of the vessels whereby CFL (CalMac Ferries Ltd) are simply observers".

The latest account of a Ferguson Marine board meeting from May shows that non-executive director Stuart Smith asked if the LNG system was a "risk to the programme".

Ship delivery director Andy Crossan said that at that point they did not have approval on the LNG system and were "working with contractors to de-risk".

A Ferguson Marine spokesman said that despite past issues "there will be no gap in terms of LNG" and that when the vessels finally set sail it will be available for use from day one.

In November, last year, Ferguson Marine said the first of the two vessels would need to use diesel for the first nine months of its services rather than LNG.

That was because the shipyard had not managed to procure sensors which the ship needed to run the LNG system.

During the summer in a progress check, Mr Tydeman said that the LNG system could only be proven "once we have agreed where the very low temperature (-170C) LNG can be safely loaded on to the ship and once the integrity of machinery has been first proven with the MGO fuel".

The Herald: David Tydeman became CEO of Ferguson Marine Port Glasgow in February 2022

He said: "We expect decisions to be made during the next three months and this highlights that Glen Sannox will be the first ship to be built and commissioned in the UK with LNG and there could be unforeseen issues during the final commissioning processes.”

One ferry user group official said there would be fears at the very least of further delay if Ferguson Marine were forced to keep the ships back until their LNG capability is resolved.

"LNG has been one of the many pains in the side of the efforts to produce these ferries from the start," he said. "It would be a real catastrophe if the attempt to be green further damages the efforts to finally get these ferries sailing for the benefit of islanders who just want a reliable service."

On Friday ministers came under fire as new estimates suggested the cost of building Scotland's ferry vessels could reach £400m.

The sum, which does not include the millions pumped into nationalised Ferguson Marine to keep it operating, amounts to over four times the £97m contract cost for the two lifeline ferries still awaiting delivery in the Inverclyde shipyard.

David Tydeman, the chief executive of Ferguson Marine indicated that it will cost an extra £240 million to build Glen Sannox and Glen Rosa on top of what was spent before nationalisation.

Some £83.25 million was spent on the ferries prior to Scottish Government taking control of the shipyard firm with a further £45m loaned.

In his latest update, Mr Tydeman says the contingency costs for both vessels could increase the overall spend even further by £30 million. And there is a potential extra spend on warranties, many of which have expired.

Glen Sannox was due in March 2024 but there remain doubts over whether that schedule will be met with Mr Tydeman saying it will "depend on how well the trial progress". It is believed Glen Rosa is now not due to be completed until May 2025.

Questions had been raised about the sanctioning the move to 'green' LNG after it was revealed work on crucial infrastructure had not started yet – while one of two LNG tanks involved in a £5m contract are no longer needed.

Questions were also raised about how the ferries will be fuelled in the wake of LNG infrastructure problems.

The Herald: The Glen Sannox

The latest completion date given by the Danish supplier is the "beginning of 2025" – well after the latest dates for the delivery to Scottish Government-controlled ferry operator CalMac of the much-delayed and over-budget vessels Glen Sannox and Glen Rosa.

Eyes have also been raised about the logistics of getting LNG to Scotland – while four new vessels being built in Turkey will not be powered by the 'green' fuel at all.

According to a 2022 Scottish Government briefing, LNG will have to be shipped from the Isle of Grain in Kent – a near 500 mile journey by road.

CalMac has been told that it is not yet feasible to use LNG-powered trucks due to the size of the fuel tanks required and a lack of refuelling infrastructure.

While there has been criticism over what has been described by some as an LNG planning 'farce', CalMac has begun moves to use Troon rather than Ardrossan for services to and from Arran for the ferries.

Because of the storage tank issues, the LNG will be pumped from trucks to the ship there.

CalMac admit in its customer messaging that truck-to-ship bunkering is "not considered a sustainable solution" which will meet the long-term demands of the new ships.

They say the typical transfer rate is too slow – typically between two and two-and-a-half hours for 20 tonnes. When the delayed fixed tank is in operation, the time will drop to between 45 and 60 minutes. The ferry operator said if tankers are required to meet the vessel during the timetabled port calls, there would be a "risk of delay caused if problems were encountered during transit".

A Transport Scotland spokesman said: “Transport Scotland, the Scottish Government, CMAL and [Ferguson Marine] meet weekly to discuss the progress of MV Glen Sannox towards handover, including the LNG system requirements, and to ensure the vessel is fully commissioned when delivered.

“The global LNG industry has an excellent safety record; permanent use and storage of LNG in the UK is subject to control by the Control of Major Accident Hazards (COMAH) regulations and the IMO's International Code of Safety for Ships (IGF Code).”